**3. Conclusion**

The low concentrations of pesticides may be used in combination with biological control agents within an IPM system to reduce the selective pressure and development of resistance in pests, but this study showed that adverse effects of fenpyroximate and abamectin on *P. plumifer* were significant, indicating that this acaricide may not be advisable for combined use with *P. plumifer* in IPM programs for controlling *T. urticae*. Even the low concentrations of acaricides that was suggested could be used in combination with biological control agents [52] had considerable adverse effects on this predator.
